Gas turbine engine combustors are generally subject to high thermal loads for prolonged periods of time. To alleviate the accompanying thermal stresses, the walls of the turbine combustor must be cooled to help increase the usable life of the turbine combustor components and therefore increase the reliability of the overall turbine engine.
An annular, impingement film cooled turbine combustor typically comprises a support shell and a set of temperature tolerant heatshield panels secured to the shell to protect the shell from hot combustion gases. A typical heatshield panel has a shield portion whose platform is rectangular or approximately rectangular. When secured to the shell, the shield is oriented substantially parallel to the shell so that one side of the heatshield, referred to as the hot side, faces the hot combustion gases and the other side, referred to as the cold side, faces toward the support shell. A principal advantage of a thermally decoupled turbine combustor is that the heatshield panels can thermally expand and contract independently of each other. This thermal independence improves turbine combustor durability by reducing thermally induced stresses. Examples of impingement film cooled, thermally decoupled turbine combustors may be found in U.S. Pat. Nos. 6,701,714, 6,606,861, and 7,140,185, commonly owned by the applicant.
Today's smaller, high efficiency turbine combustors require precise partitioning of airflow for efficiency, emissions, performance and operational requirements. This includes the objective of minimizing the volume of cooling airflow required to cool the turbine combustor, and tight control of that airflow to maximize cooling benefits for better thermal regulation of the turbine combustor components.